NullReferenceException using LINQ

Question

I have trouble to getting my linq line to work.

var result = databaseObjects.Where(dbo => dbo.GetType() == typeof(Model.DatabaseTable) ? (dbo as Model.DatabaseTable).FullName.Equals(name) : dbo.Name.Equals(name));

I tried to use the method from an answer to this question to make it work. I think i know what is wrong, DatabaseObject is a abstract class, and i want to to avoid to use FullName property on everything else than DatabaseTable, but from what i can see it does check on it.

EDIT: The Error was:

System.NullReferenceException was unhandled
{"Object reference not set to an instance of an object."}

Problem was i forgot to assign DatabaseObject.Name, DatabaseTableObject.FullName was assigned.

i forgot to assign Name, on the objects other than DatabaseTable, a stupid mistake, and i kept looking into the linq expression, which was not wrong :) — Henrik Bøgelund Lavstsen
– Henrik Bøgelund Lavstsen, Commented Dec 11, 2012 at 14:47

James · Accepted Answer · 2012-12-11 14:35:06Z

3

Looks as though either FullName or Name is null on one of your dbo objects. To verify change your code to:

var result = databaseObjects.Where(dbo => dbo.GetType() == typeof(Model.DatabaseTable) ? (dbo as Model.DatabaseTable).FullName == name : dbo.Name == name);

It's shouldn't throw an exception.

answered Dec 11, 2012 at 14:35

James

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2 Comments

Henrik Bøgelund Lavstsen Over a year ago

I know found out during maintenence here on stack overflow :) wanted to pull question down before that, but was too slow. Thank you anyway

Coding Flow Over a year ago

Leave the question it may help others. I would even sugest updating the question to show what error message you were getting.

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